Emulsion polymerization of water insoluble ethylenic monomers



United States Patent ice 3,062,765 EMULSION POLYMERIZATION OF WATER IN-SOLUBLE ETENIC MONOMERS Patsy 0. Sherman, St. Paul, and Samuel Smith,Mendota Heights, Minn., assignors to Minnesota Mining and ManufacturingCompany, St. Paul, Minn., a corporation of Delaware No Drawing. FiledApr. 3, 1957, Ser. No. 650,294

15 Claims. (Cl. 26029.6)

This invention relates to the production of polymers and moreparticularly to an improved process for emulsion-polymerizing certainwater-insoluble ethylenic monomers.

The process of emulsion-polymerization is of great industrialimportance, being used in the large scale preparation of most rubberypolymers and copolymers and of some non-rubbery polymers. The latexeswhich are thus produced are sometimes coagulated to recover the solidpolymers, but they can be and are often used directly, such as forexample in latex paints, adhesives, coatings for textiles and paper,etc.

'Heretofore it has been the general practice to carry out polymerizationin water-oil types of emulsion with the aid of emulsifying agents and inthe presence of free radical initiators. Although some monomersemulsionpolymerize easily, others, especially thoseof high molecu; larweights and consequent low water solubility, can be polymerized by thismethod only with difficulty and in poor yield. Thus, specializedprocesses have been resorted to for the group of substantiallywater-insoluble monomers, e.g. the use of special emulsifiers, themaintenance of a high concentration of emulsifier to maintain latexstability and pre-emulsification of the monomer in the water withhigh-speed agitation, followed by slow and carefully regulated agitationduring polymerization to avoid monomer droplet growth. In anotherprocess for the preparation of aqueous dispersions of polymers, bulk,solution or suspension polymerized materials are dissolved in a largequantity of solvent, the solution is dispersed in water containing arelatively large quantity of emulsifier with high speed agitation .andthe solvent is removed.

A number of difficulties attend these specialized processes and tend toreduce their utility. They are difficult and expensive processes tocarry out. Their products often contain sufiicient emulsifier to renderfilms coated from them water sensitive. The latexes thus preparedinvariably have large particle sizes; and this either renders themunstable on storage for even short periods, particularly with dilution,changes of temperature, changes of pH, etc. (i.e. with particles of5,000 A. diameter or larger), or renders them undesirable for coatingsbecause of graininess, lack of luster, or microscopic pinholes3,062,765. Patented Nov. 6, 1962 rated monomers. It is another object ofthe invention to provide a process for emulsion-polymerizing certainethylenically unsaturated monomers having high molecular weight, whichare capable of undergoing free radical addition polymerization, toproduce latexes which are comparable to normal latexes of monomers ofrelatively lowmolecular weight in stability, particle size, freedom fromexcess emulsifier, and the like. Other objects of the invention will beapparent from the following disclosure.

In accordance with the above and other objects of the present inventionit has been found that the emulsionpolymerization of ethylenicallyunsaturated monomers capable of undergoing free radical additionpolymeriza tion which, because of-their high molecular weight andwater-insolubility are difficult or impossible to emulsionp-olymerize byconventional methods, can readily be accomplished by carrying out thepolymerization in an aqueous medium containing about 5% to about 50% ofan inert water-soluble organic solvent in which the mono mer is at leastslightly soluble.

The process of the invention using a water-organic solvent emulsionmedium is employed with monomer systems capable of undergoing freeradical addition polymerization, of which at least one monomer issoluble in an amount less than one part by weight in a mixture of partsby weight of methanol and 25 parts by weight of water at 25 C. By theuse of the process, monomers which cannot be successfullyemulsion-polymerized using the processes heretofore known to the art canbe emulsion-polyrnerized in good yield to produce stable, usefullatexes. Thus, the process of the invention produces un.-' expectedlyuseful results within the area of its operation. These results areespecially unpredictable in the case of the fiuoro-carbon-containingmonomers, which could not be expected to act in any way comparable tothe corre: sponding hydrocarbon analogues thereof.

I A convenient method of determining whether a par ticular monomer issufficiently water-insoluble so that the emulsion polymerization processof the invention using a waterzorganic medium is advantageously appliedthereto is the following: (1) a solution of one gram of the monomer in80 grams of absolute methanol is prepared, and (2) a measured amount ofwater is cautious- 1y added to this solution until an endpoint isindicated by the appearance of turbidity or phase separation. If themonomer cannot be completely dissolved in the methanol, or if turbidityor phase separation appear before 25 milliliters of water have beenadded, the present process can be advantageously employed. forpolymerization. Typical examples of such monomers are: lauryl, tridecyl,tetradecyl, hexa-decyl and octadecyl acrylates, methacrylates and vinylethers; higher vinyl esters such as vinyl 'laurate, vinyl myristate,vinyl palrnitate and vinyl stearate; higher l,l-dihydroperfiuoroalkylacrylates and methacrylates such "as 1,1-dihydroperfluorooctylmethacrylate and 1,1-dihydroperfluorodecyl acrylate; higher w-(N-alkyl,N-perfluoroalkane) aminoalkyl acrylates and methacrylates; higherfluorinated vinyl esters such as vinyl, N-ethyl, N-perfluorooctanesulfonyl glycinate, and the like.

The inert solvent which is used in the process is a water-solubleorganic solvent which will not react with the monomer. Examples ofsolvents which are suitable for the practice of the invention are loweralkanols, such as methanol, and ethanol; water-soluble glycols, such asethylene glycol, propylene glycol; water-soluble ketones such as acetoneand methyl ethyl ketone; cyclic ethers, such as dioxane; cyclic aminessuch as pyridine; and the like. While it is necessary to determineempirically which specific solvent will produce optimum results with anyparticular monomer system, any solvent of the type described willproduce useful results in the process of the invention.

A further distinguishing characteristic of the relatively high molecularweight monomers which are useful in the process of the invention, aswell as the organic solvents useful therein, is that the monomer must besoluble to the extent of at least about one gram of monomer in 100 ml.of the particular solvent which is to be added to its emulsion medium.This requirement may also be expressed as requiring the monomer to besoluble to the extent of at least about 1% w./v. in the organic solvent.

In the process of the invention, the selected inert, water-solubleorganic solvent is added to the aqueous medium in amount of about 5 toabout 50% by weight of that of the water present. Below about 5% concentrations of the solvent, its eifects are very slight, while atconcentrations over about 50% the formation of precoagulum (anundesirable precipitate of polymer) tends to become excessive, therebyreducing the overall conversion of monomer to latex. The maximumbenefits of the process are invariably realized when the solventemployed is present in concentration ranging from to 40% of the amountof water, and this range is therefore preferred.

In carrying out the process, once the latex has been formed it is, ofcourse, independent of the organic solvent, which can be removed bysteam or vacuum distillation or other comparable techniques, and can bereplaced by water without adversely afiecting the properties of theemulsion. This may be done if the odor or the flammability of thesolvent is undesirable in the particular application to which the latexis put.

Having thus broadly described the process of the invention, there areappended several specific examples of its operation. These examples areto be understood as illustrative only and should not be construed asbeing limiting in any sense. Thus, for example, any other conventionalwater-soluble free radical initiator may be used in place of thepotassium persulfate used in the examples (e.g. ammonium persulfate,hydrogen peroxide, sodium perbenzoate, etc.) as well as ultravioletlight or ionizing radiation. Furthermore, promoters can be used ifdesired, such as sodium bisulfite, ferrocyanide salts, ferrous salts andamines, and the like. Other variations known in the art can be used inconjunction with the process of this invention since the advantageouspresence of the specific solvents which are employed does not interferewith the operation of the conventional means known to the art to beuseful in processes involving emulsion-polymerization, and the use ofsuch variation is contemplated to be within the scope of the invention.

The procedure used in each of the examples, and the amounts of theingredients employed, is as follows, except as otherwise specified:

A suitable vessel is charged, frozen in liquid air, evacuated to apressure of less than 0.01 mm. of mercury, thawed and refrozen,re-evacuated and finally sealed. The vessel is then agitated in a 50 C.water bath for 16 hours. The charge, except where otherwise specified,is 100 parts by weight of monomer, 5 parts of emulsifier, V2 part ofpotassium persulfate, and 180 parts of medium.

Relative molecular weights of polymers are indicated by inherentviscosity measurements in a number of the examples.

4 EXAMPLE 1 The Emulsion Polymerization of Vinyl Stearate, a TypicalLang Chain Hydrocarbon Monomer Suitable f r Use in the Process of theInvention To determine suitability of vinyl stearate for advantageoususe in the process, water was titrated at room temperature into asolution of one gram of vinyl stearate in eighty grams of absolutemethanol until the appearance of turbidity which remained afterthoroughly mixing the solution. It was found that eight milliliters ofwater were required. From this it is seen that the emulsionpolymerization of vinyl stearate will be improved by the addition of asuitable organic solvent to the emulsion medium.

The procedure set forth above was used for polymerizing each batchcontaining the ingredients and amounts thereof specified. Both anionicand cationic emulsifiers were used. In this connection, anionic (e.g.sodium stearate, potassium oleate, sodium lauryl sulfate, etc.),cationic (e.g. dodecylamine hydrochloride, cetyl trimethyl ammoniumbromide, etc.) and nonionic (e.g. alkyl aryl polyether alcohols)emulsifiers can all be used in the practice of our invention in the samemanner as they are when a conventional aqueous medium is used.

The following table shows the results obtained when vinyl stearate wassubjected to emulsion polymerization under varying conditions, in mediacontaining various amounts of organic solvents coming within the scopeof the invention. An attempt to produce a latex in a medium containingwater only is included for purposes of comparison.

TABLE 1 Con- Averversion age Emulsifler Medium amt. to latex Remarkslatex, particle percent size,A.

. Sodiumstearate Water, 180 47 30, 000 Coagulatcd substantmllyimmediately on standing Do Water, 135; 77 900 Stable, fluid methanol,45. latex. Do Water, 126; ace- 06 600 Viscous, stable tone, 54. latex.Sodium stearate do 82 1,000 Stable, fluid (3 part latex. Do leeylamineWater, 144; aee- 1,000 Do.

H01. tone, 36.

EXAMPLE 2 Twenty milliliters of water were tolerated by a solution ofone gram of lauryl methacrylate in eighty grams of methanol at roomtemperature before turbidity was observed thus indicating thesuitability of this monomer for conversion to a latex in a mediumcontaining an organic solvent according to the process of the invention.Significant and unexpected improvements in both conversion and qualityare shown in the emulsion polymerization of lauryl methacrylate when anorganic solvent is added to the aqueous emulsion medium.

Likewise, seven milliliters of water were tolerated at room temperatureby octadecyl methacrylate in the titration test. The successfulemulsion-polymerization of octadecyl methacrylate (which will notreadily emulsionpolymerize by conventional methods) is shown with fourdifferent emulsifiers using waterzacetone media.

The following table shows the results obtained: ity or percentconversion in the emulsion polymerization TABLE II Conver- AverageMonomer Emulsrfier Medium, amt. sion to latex Appearance of latex (n) 1latex, particle percent size, A,

Lauryl methacrylate I Duponol ME 3 Water, 180 52 1,730 Laltr% e amountof precoagu- 0.93

a mu. do. Water, 144; acetone, 36.- 92 1,110 Very small amount of pre-1.31

coagulation, Octadecyl methacrylate dfl do 87 800 Somewhat viscouslatex"--- 0. 48 Dodeoylamine hydrochlor1de .do 95 1,000 Stable, fluidlatex 0.61 Sodium stearate. Water, 108; acetone, 72 59 Someprecoagulation- 0. 39 do Water, 90; acetone, 90-.- 60 do 0.25 Potassiumsalt of N-ethyl, N- Water, 108; acetone, 72.. 78 Small amount ofprecoagu- 0.36

perfluoro-octane sulfonyl glylation. cine. ...-do Water, 90; acetone,90"- Total precoagulation 1 Inherent viscosity. 2 Lauryl methacrylateand octadecyl methacrylate are both more than soluble in acetone at roomtemperature. 3 Four parts of emulsifier were used. 4 Not determined.

EXAMPLE 3 V of the former with the addition of an appropriate organic Inthis example are illustrated higher molecular solvent to the emulsionmedium of the former, but that weights which can be Obtained by usingthe present Proc such lmprovements could be expected with the latter.

ess as shown by the increased inherent viscosity of the Theseindications are borne Out y the data Set forth n products, and also thesharp line of demarcation which Table III.

v TABLE III v I Conver- Extent (n) of (1 1 of Monomer Emulsifler Medium,amt. sion to of preemulsipreco- Appearance of latex, coagufied agulationlatex percent lation, polymer percent 1,1-dihydroperfluorohexylDoclecylamine 'hydrochlo- Wat r, 180 99 0 1.10 Clearfluid latex.

methacrylate. ride. rln wger, 135; methanol, 100 O 0.92 Do. 11-dihydroperfluoro-octyl do-. Water, 18 30 0.21 0.77 Fluid latex,clear..

methacrylate. 13 2 I do W4a5ter, 135; methanol, 100 0 0.70 D0. DPotassium salt of a highly Water, 180 18 so 0.49 0. 96 Do,

fluorinated carboxylic acid. 1 an Water, 126; acetone, 54.- 100 0 1. 24D0.

1 Inherent viscosity. 2 Both of these monomers are over 1% soluble inmethanol and infinitely miscible with acetone at room temperature.

distinguishes the scope of operation of the process as EXAMP 4 appliedto the higher members of series of monomers, as compared with theresults using the lower members of The data set forth in the followingtable show the eifects th i of increasing (up to an optimum value) thepercentage of The average particle size ineach of the latexes proorganicsolvent in the medium in the process of emulsionduced was less than900A. polymerization of octadecyl acrylate with a hydrocarbon s l ti fone gram f 1,l-dihydroperfiuorohexylemulsifier and with a fluorocarbonemulsifier. Improvemethacrylate and1,l-dihydroperfluorooctylmethacrylate ments in the percentage conversionof monomer to latex, in eighty grams of absolute methanol tolerated theaddimolecular weight of the polymer contained in the latex tion of 40and 20 milliliters of water respectively at room (a shown by theinherent viscosity), latex particle size temperature b f t bidity orphase separation. It was and latex stabllity are shown to be broughtabout by the thus shown that there would be no improvement of qualadltlon 0f the solvent.

' TABLE IV Conver- (11)1 of Average Monomer Emulsifler Medium, amt. sionto Emulsilatex Appcarance of latex latex, fied particle percent polymersize, A.

Octadecyl acrylate Sodium stearate Water, 180 49 2 10,000 Unstable,1coagulated almost imme 1a. e y, Water, 171; acetone, 9... 54 0. 29 10,000 Do. Water, 162; acetone. 18 0.28 800 Viscous, stable. Water, 153;acetone, 27-. 89 0. 34 600 Viscous, stable latex. Water, acetone, 45 960. 61 600 Do. Water, 126; acetone 54.- 100 0.62 600 Do, Potassium saltof N-ethyl, N- Water, 0 Complete preeoagulation.

perfluorooctane sulfonyl glyme. e Water, 153; acetone, 27 62 0.32 1, 000Stable, fluid, latex:

Water, 126; acetone, 54.. 97 0. 48 1,000 Do,

1 Inherent viscosity. 2 Octadecyl acrylate is about 1% soluble inmethanol and more than 10% soluble in acetone at room temperature,

aoeayree 7 EXAMPLE The comparative results (both in quality and inpercent conversion of monomer to latex polymer) of carrying out theemulsion-polymerization of several fluorocarbon 8 ditficultly emulsionpolymerizable monomers have interesting and unusual utility. Permanentinternal plasticization can be achieved in such polymers, the relativelywater-insoluble long-chain monomer acting as the plasmonomers in waterand in aqueous solutions of organic 5 ticiZer. This plasticizer systemhas the advantages over solvents are illustrated in the following table.regular plasticizer systems of not migrating and of not TABLE V Conver-Average Monomer Emulsifier Medium, amt. sion to latex Appearance oflatex latex, particle percent size, A.

1. 1 i lydropcrfluorohexylacry- Dodecylamine hydroehloride Water, 180 97900 Clear, stable.

-d0 Water, 144; acetone, 36-- 100 900 Do. 1,1-dlhydroperfluorodecylacry- Potassium salt of a highly fluori- Water,180 0 Total, precoagulation.

late. nated carboxylic acid.

do Water, l35;methanol,45 88 900 Clear, stable. fl-(N-ethyl,N-periluorohexane Potassium salt of N-etllyl, N-per- Water, 180 Cloudy,unstable, large sulfonyl)-amiuoethylacrylate. fiuorooct'me sultonylglycine amount of precoagulation.

Water, 126; acetone, 54" Clear, stable. fl-(N-cthyl, N-pcrfiuorooctaneWater, 180 Tetalprecoaguletion.

sulfonyD-aminoethyl acrylate.

Wat Cloudy, stable.

Potassium salt of a highly fluoroinated carboxylic acid.

Potassium salt of a highly fiuoroinated carboxylic acid (10 parts).

Wot

er, 126; acetone, 54" er, 180

Cloudy, almost total precoagulation.

Cloudy, viscous, unstable.

Coagulated substantially 1mmediately. Potassium salt ofahlghly fiuoroi-Water, 108;methanol, 72 94 i Slightlycloudy, stable.

nated carboxyllc acid. (lo Water, 126; acetone. 54;.- 93 900 Cloudy,stable. fl-( -pr pyl, N-perfluoro-octane Potassium salt of N-perfluoro-Water, 108; ethanol, 72..

sulfonyD-amlnoethyl acrylate. octane sulfonyl glycine.

' w' 01 mer EXAMPLE 6 being difiicult to mix homogeneously 1th the p yEmulsion-Copolymerization of Vinyl Chloride and Vinyl Stearate Vinylchloride is sutficiently water-soluble to emulsionhomopolymerize easilyin water alone as a medium, whilst vinyl stearate is sufiicientlywater-insoluble so that its emulsion-homopolymerization is extremelydifficult by heretofore known methods.

The following were charged to each of two crown cap pressure bottles:

50 pts. vinyl chloride 50 pts. vinyl stearate Water and acetone as shownin the table set forth below 4 pts. sodium stearate 0.5 pt. potassiumpersulfate Excess vinyl chloride was added as the last ingredient andthe excess was permitted to volatilize, thus purging the bottles of airprior to scaling. The bottles were tumbled end-over-end in a 50 C. bathuntil about conversion to polymer was obtained. The polymer was thenseparated, washed with water and finally extracted with boiling methanolin a soxhlet apparatus to remove all unreacted vinyl stearate. Chlorinecontents were then determined on the dry polymer. The results are shownThis example demonstrates the important results obtained with theprocess of the invention in copolymerization reactions involving atleast one long chain, highly water insoluble monomer, in producingsuperior latexes and increasing the rate of combination of the longchain monomer with smaller, more water-soluble comonomers.

These and similar emulsion copolymers of normally easily emulsionpolymerizable monomers with normally as are regular plasticizers used inlatex formulations. As in other plasticizers the long-chain comonomeroften makes it possible to form films at room temperature from theemulsion state. Unplasticized polyvinyl acetate, for example, applied toa surface from an emulsion and dried at room temperature does not form acontinuous film. In order to form a continuous film, it must be heatedto at least 35' C. and this makes it impractical for some applications(e.g., latex paints). An emulsion of an %:15% copolymer by weight ofvinyl acetate and vinyl stearate, however, does form a continuous filmat room temperature upon drying. It will thus be seen that the processof the invention produces highly advantageous and desirable results.

A useful procedure utilizing the novel features of the invention andsuitable for production of large amounts of useful latexes isillustrated by the following example.

EXAMPLE 7 A 75 gallon glass-lined kettle equipped with a paddle stirrerand means for heating was charged with the following ingredients:

The water was placed in the kettle first and was boiled to expeldissolved air. The emulsifier was then dissolved in the hot water whilestirring under a blanket of nitrogen. The acetone and the monomer wereseparately mixed and the mixture was added. The temperature was thenadjusted to 50 C. and the potassium persulfate was added. The contentsof the kettle were then stirred. Nitrogen pressure of 18 p.s.i. wasmaintained in the kettle throughout the period of reaction. After abouttwo hours at 50 C., polymerization was essentially complete, butstirring at this temperature was continued for an additional two hourperiod. A complete conversion to polymer was obtained, of which waspresented in stable latex form. The average latex particle diameter,

9 measured by light scattering techniques, was of the order of 1000 A.The latex had inherent viscosity=0.41.

As used herein, the term inherent viscosity signifies the numberobtained by dividing the natural logarithm of the relative viscosity bythe concentration of the polymer in grams per 100 ml. of the solvent inwhich viscosity is determined. The relative viscosity is the ratio ofsolution viscosity to solvent viscosity. In the case of hydrocarbonpolymers, inherent viscosity was determined using 0.15% solution in 4:1benzenezisopropanol mixtures; in the case of fluorocarbon polymers,inherent viscosity was determined using 0.15% solution in 2:1 methylperfluorobutyrate:acetone mixtures. All determinations were made at 25C.

The useful latexes of the present invention as hereinabove described arefurther characterized by the fact that they are stable latexes havingparticle sizes of the order of 1000 A. (i.e., in the range of about 700to about 1500 A.), comprised of polymers made from significant amountsof monomers of relatively high molecular weight.

We claim:

1. The process for emulsion polymerization which comprises charging to asuitable reaction vessel a waterinsoluble, high-molecular weight monomercontaining from 12 to 22 carbon atoms and selected from the classconsisting of alkyl acrylates, alkyl methacrylates and alkyl vinylethers and vinyl esters of long-chain fatty acids, said monomer beingsoluble in an amount less than about 1 part by weight in a mixture of 80parts by Weight of methanol and 25 parts by weight of water at 25 C., anaqueous medium containing about 5 percent to about 50 percent of awater-soluble organic solvent which is substantially inert with respectto reaction with the monomer and with respect to attack by free radicalspresent during the course of the process and which is capable ofdissolving at least about 1 percent w./v. of the said monomer at 25 C.,and an emulsifier, and agitating the resulting charge under free radicalconditions until appreciable polymerization has occurred.

2. The process for emulsion polymerization which comprises charging to asuitable reaction vessel a plurality of monomers including at least onewater-insoluble, highmolecular Weight monomer containing from 12 to 22carbon atoms and selected from the class consisting of alkyl acrylates,alkyl methacrylates and alkyl vinyl ethers and vinyl esters oflong-chain fatty acids, said monomer being soluble in an amount lessthan 1 part by weight in a mixture of 80 parts by weight of methanol and25 parts by weight of water at 25 C., an aqueous medium containing fromabout 5 percent to about 50 percent of a water-soluble organic solventwhich is substantially inert with respect to reaction with the monomersand with respect to attack by free radicals present during the course ofthe process and which is capable of dissolving at least about 1 percentw./v. of the said water-insoluble monomer at 25 C., and an emulsifier,and agitating the resulting charge under free radical conditions until alatex has formed.

3. The process of claim 1 wherein the organic solvent is acetone.

4. The process of claim 1 wherein the organic solvent is methanol.

5. The process of claim 1 wherein the organic solvent is ethanol.

6. The process of claim 1 wherein the monomer carries a hydrocarbonchain.

7. The process according to claim 1 wherein the monomer is afluorocarbon-chain containing monomer.

8. The process for emulsion polymerization which comprises charging to asuitable reaction vessel vinyl stearate monomer, an aqueous mediumcontaining from about 5 percent to about 50 percent of a water-solubleorganic solvent which is substantially inert with respect to reactionwith the monomer and with respect to attack by free radicals presentduring the course of the process and which is capable of dissolving atleast about 1 percent w./v. of the said monomer at 25 0., and anemulsiher, and agitating the resulting charge under free radicalconditions until appreciable polymerization has occurred.

9. The process of claim 1 wherein the organic solvent is present inamount of from 10% to 40% of the aqueous medium.

10. The process for emulsion polymerization which comprises charging toa suitable reaction vessel vinyl stearate monomer, an aqueous mediumcontaining from about 10 percent to about 40 percent of methanol and anemulsifier, and agitating the resulting charge under free radicalconditions until appreciable polymerization has occurred.

11. A stable latex of particle size of the order of about 1000 A.produced by charging to a suitable reaction vessel a water-insoluble,high-molecular weight monomer having from 12 to 22 carbon atoms andselected from the class consisting of alkyl acrylates, alkymethacrylates and alkyl vinyl ethers and vinyl esters of long-chainfatty acids, said monomer being soluble in an amount less than about 1part by weight in a mixture of parts by weight of methanol and 25 partsby weight of water at 25 C., an aqueous medium containing about 5percent to about 50 percent of a water-soluble organic solvent which issubstantially inert with respect to reaction with the monomer and toattack by free radicals present during the course of the process andwhich is capable of dissolving at least about 1 percent w./v. of thesaid monomer at 25 C., and an emulsifier, and agitating the resultingcharge under free radical conditions until a latex has formed.

12. A latex according to claim 11, wherein the hydrocarbonchain-containing monomer is vinyl stearate.

13. A latex according to claim 11, wherein the hydrocarbonchain-containing monomer is lauryl methacrylate.

14. A latex according to claim 11, wherein the hydrocarbonchain-containing monomer is octadecyl methacrylate.

15. A latex according to claim 11, wherein the hydrocarbonchain-containing monomer is octadecyl acrylate.

References Cited in the file of this patent UNITED STATES PATENTS2,118,864 Reppe et a1. May 31, 1938 2,444,396 Collins et al June 29,1948 2,584,306 Theobald Feb. 5, 1952 2,686,165 Fryling et al Aug. 10, 1

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,062,765 November 6, 1962 Patsy 0,, Sherman et a1,

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 8, line 74, for "presented" read present Signed and sealed this30th day of April 1963;

(SEAL) Attest:

DAVID L. LADD Commissioner of Patents ERNEST W SWIDER Attesting Officer

1. THE PROCESS FOR EMULSION POLYMERIZATION WHICH COMPRISES CHARGING TO ASUITABLE REACTION VESSEL A WATERINSOLUBLE, HIGH-MOLECULAR WEIGHT MONOMERCONTAINING FROM 12 TO 22 CARBON ATOMS AND SELECTED FROM THE CLASSCONSISTING OF ALKYL ACRYLATES, ALKYL METHACRYLATES AND ALKYL VINYLETHERS AND VINYL ESTERS OF LONG-CHAIN FATTY ACIDS, SAID MONOMER BEINGSOLUBLE IN AN AMOUNT LESS THAN ABOUT 1 PART BY WEIGHT IN A MIXTURE OF 80PARTS BY WEIGHT OF METHANOL AND 25 PARTS BY WEIGHT OF WATER AT 25*C., ANAQUEOUS MEDIUM CONTAINING ABOUT 5 PERCENT TO ABOUT 50 PERCENT OF AWATER-SOLUBLE ORGANIC SOLVENT WHICH IS SUBSTANTIALLY INERT WITH RESPECTTO REACTION WITH THE MONOMER AND WITH RESPECT TO ATTACK BY FREE RADICALSPRESENT DURING THE COURSE OF THE PROCESS AND WHICH IS CAPABLE OFDISSOLVING AT LEAST ABOUT 1 PERCENT W./V. OF THE SAID MONOMER AT 25*C.,AND AN EMULSIFIER, AND AGITATING THE RESULTING CHARGE UNDER FREE RADICALCONDITIONS UNTIL APPRECIABLE POLYMERIZATION HAS OCCURRED.